1. Field of the Invention
This invention relates to the field of pressure relief valves and more particularly to the field of dual directional relief valves.
2. Background Discussion
Pressure relief valves are widely used in systems handling fluid under pressure to protect the elements of the system including the tanks, lines, and pumps from damage. In most cases, the manufacturers usually recommend and often require that relief valves be used in the systems to maintain the warranty but more importantly, to protect the operators from harm and to avoid potentially dangerous leaks and spills.
The most commonly used and commercially available releif valves are unidirectional meaning that they only work in one direction. Consequently, if fluid is always being pumped for example in one direction from a first tank to a second tank, a unidirectional valve correctly installed in the system will generally protect the elements on the positive side of the pump. However, in a reversible system where fluid is being pumped for example from the first tank to the second tank part of the time and from the second to the first tank at other times, the operator must install two relief valves in the system to truly protect it. Unfortunately, such relief valves are relatively expensive and many operators commonly end up either installing no relief valve at all or taking their chances and installing only one relief valve to protect only one side of their system. Also, and regardless of how many unidirectional relief valves the operator decides to install, such valves always present the inherent problem that they must be installed correctly because if they are installed backwards, they are rendered useless as protective devices. In many situations, it is easy to correctly install such valves to properly protect the system. However, in an equal number of situations, it is not so easy to correctly install them. This is true particularly when the operator is in the field in a hurry with mud and dirt covering the equipment, the operator's manual not readily available, the lighting poor, directional arrows (if any) on the equipment partially or completely obliterated, and the pump lines literally going everywhere.
With these problems in mind, the present invention was developed. With the present invention, a simple and effective valve design is now available for relieving dangerously high pressure in pump systems or any other systems handling fluid under pressure. The valve is dual directional in the sense that it will relieve high pressure regardless of the flow direction through the system. Also, because it is dual directional, it cannot be installed backwards as is the case with many unidirectional relief valves.